【发布时间】：2015-02-24 10:47:55
【问题描述】：
我的 iOS 天气应用程序出现了一些问题。 我是 xCode 编程的新手，所以这可能是一个愚蠢的错误。 无论如何，问题是：我试图在我的单页应用程序中添加一个刷新按钮。该按钮有一个关联的 IBAction 函数，因此当它被按下时它应该被隐藏并且应该出现活动指示器。 那就是函数：
@IBAction 函数重载() {
refreshButton.hidden = true
refreshActivityIndicator.hidden = false
refreshActivityIndicator.startAnimating()
}
这就是变量的声明：
@IBOutlet weak var refreshButton: UIButton!
@IBOutlet weak var refreshActivityIndicator: UIActivityIndicatorView!
当我运行应用程序并按下刷新按钮时，应用程序崩溃并出现此错误：
@UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate {
控制台不显示任何其他内容。 可能是什么问题？
// APPDELEGATE.SWIFT
导入 UIKit
@UIApplicationMain 类 AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
application.setStatusBarHidden(true, withAnimation: .None)
return true
}
func applicationWillResignActive(application: UIApplication) {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}
func applicationDidEnterBackground(application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
func applicationWillEnterForeground(application: UIApplication) {
// Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}
func applicationDidBecomeActive(application: UIApplication) {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
func applicationWillTerminate(application: UIApplication) {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
}
//VIEWCONTROLLER.SWIFT 导入 UIKit 导入基金会
类视图控制器：UIViewController {
private let apiKey = "447073dc853014a6fa37376c43d8462b"
@IBOutlet weak var iconView: UIImageView!
@IBOutlet weak var currentTimeLabel: UILabel!
@IBOutlet weak var temperatureLabel: UILabel!
@IBOutlet weak var humidityLabel: UILabel!
@IBOutlet weak var precipitationLabel: UILabel!
@IBOutlet weak var summaryLabel: UILabel!
@IBOutlet weak var refreshButton: UIButton!
@IBOutlet weak var refreshActivityIndicator: UIActivityIndicatorView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
refreshActivityIndicator.hidden = true
// base URL
let baseURL = NSURL(string: "https://api.forecast.io/forecast/\(apiKey)/")
// add coordinates to base url (API syntax)
let forecastURL = NSURL(string: "44.698150,10.656846", relativeToURL: baseURL)
// NSURL SESSION
//The NSURLSession class and related classes provide an API for downloading content via HTTP. This API provides a rich set of delegate methods for supporting authentication and gives your app the ability to perform background downloads when your app is not running or, in iOS, while your app is suspended. With the NSURLSession API, your app creates a series of sessions, each of which coordinates a group of related data transfer tasks. For example, if you are writing a web browser, your app might create one session per tab or window. Within each session, your app adds a series of tasks, each of which represents a request for a specific URL (and for any follow-on URLs if the original URL returned an HTTP redirect).
let sharedSession = NSURLSession.sharedSession()
let downloadTask : NSURLSessionDownloadTask = sharedSession.downloadTaskWithURL(forecastURL!, completionHandler:
{ (location: NSURL!, response: NSURLResponse!, error: NSError!) -> Void in
if (error == nil) {
let dataObject = NSData(contentsOfURL: location) // convert in NSData object
// serialize NSData object in Json as Dictionary
let weatherDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataObject!, options: nil, error: nil) as NSDictionary
// instance of Current (Current.swift) init with weatherDictionary
let currentWeather = Current(weatherDictionary: weatherDictionary)
// we put the code in the main queue cause this is relative the UI, that have the first thread (concurrency)
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.temperatureLabel.text = "\(currentWeather.temperature)"
self.iconView.image = currentWeather.icon!
self.currentTimeLabel.text = "At \(currentWeather.currentTime!) it is"
self.humidityLabel.text = "\(currentWeather.humidity)"
self.precipitationLabel.text = "\(currentWeather.precipProbability)"
self.summaryLabel.text = "\(currentWeather.summary)"
// Stop refresh animation
self.refreshActivityIndicator.stopAnimating()
self.refreshActivityIndicator.hidden = true
self.refreshButton.hidden = false
})
}
})
downloadTask.resume() // call sharedSession.downloadTaskWithURL -> store json data in location (local temporary memory)
}
@IBAction func reload() {
println("PRESSED")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
我没有任何 .h 或 .m 文件。
【问题讨论】：
-
请检查哪一行发生了崩溃。在 func reload() 处使用断点并查看崩溃发生在哪里。要更详细地调试，请在重新加载函数中放置以下条件 if(refreshButton.hidden) { refreshButton.hidden = false; } else { refreshButton.hidden = true;} 看看这是否有效。另外请发布更多关于按钮和活动指示器初始化的代码。
-
@ArunGupta 我试图删除 func 中的所有代码，但它继续崩溃
-
@ArunGupta 也尝试检查是否 (button != nil) 但没有成功
-
您是否检查过将属性设置为强
-
@サンディープ 不，我没有。我正在学习teamtreehouse的课程，并且我已经按照老师的方式完成了所有事情。
标签： ios xcode swift uibutton ibaction